Means for promoting combustion



J- B. SMITH.

MEANS FOR PROMOTING COMBUSTION. APPLICATI-ON FILED mu. I5, 1919.

- ltmm al UNITED srATEs' JOHN BUIDD SMITH, or scorn: ORA GE, NEW'JERSEY.

MEANS FOB PBIOMQTING COMBUSTION. .n

Application filed. January it, 1919; se iainoiarnam.

new and useful Improvements in Means for 7 Promoting Combustion, ofwhich the following is a specification.

The present invent on relate'sto improvements-in means for promotlngcombustion.

It is generally known. and well understood' that in the operationofstoves and furnaces,

to which my improvement is particularly directed, combustion isincomplete. Various forms of devices have become known by which morecomplete combustion is obtained. My invention relates particularly tothat class of devices which are associated with a flue or Stovepipe andserve the purpose of preheating air and distributing itin heatedcondition into the body of gases passing through the flue or pipe topromote a secondary combustion.

It is the principal object of this invention to provide a device of thecharacter re-. 7 ferred to which is exceedingly simple in constructionand operation, which can be manufactured at a low price and which isuniversally adaptable.

Broadly stated my invention consists in an arrangement whereby a minimumlength of plpe section is'used for preheatmgthe air to the requiredtemperature.

In its more specific aspect the invention consistsin mea-n's for passingthe air tobe heated through a heat zone adjacent the pipe'circumferentially thereof instead of longitudinally thereof.

The ob'ects and the principle of opera 7 tion will be more clearlystated in the specification and the characteristic features moreparticularly pointed out in the claims.

For a fuller understanding reference is had to the accompanyingdrawings, in which- Figure 1 is a central section through a length ofstove pipe embodying my inven-' tion; and

Fig. 2 a similar section showing the preferred embodiment of theinvention.

In Fig. 1 10 represents a pipe section of short length and adapted to beconnected to the usual outlet nipple of a stove'or other pipe section.

Ordinarily a plurality of stove pipe sec tions of various lengths arecombined to Specification of Letters Patent.

" ally affecting the draft.

I Patented Sept. 21,1920.

point of a flue. I

Along the inner surface oftlie section 10, 1s dlsposed a-narrow tubularelement 13 dc fining ,wlth the wall of the pipe section 10 an airchamber 11. One or more openings 12 in the wall of the pipe section 10admit.

air to this air chamber and perforations 1a in the wallof the tubularelement 18 afford a communication between the air chamber and theinterior of the pipesection.

The air chamber is exposed to the hot at any desired.

t EN :OLFFI-CE- form a pipe flue for passing the products of combustionto the chimney; The section 10 is purposely made of shortlength so thatit ;may be conveniently inserted gasesand the flames and is therebyintensely heated. The cold air enters the air chamber through theopening or openings 12 and 7 passes through the air chamber and theperforations 14 into the fiueQhThe perforations 14' are preferablydisposed opposite the.

opening 12.- .7 a I a The air chamber 11 is so constructed that normallya definite quantityof air is heated to a high temperature, thequantityof air with its complement of oxygen being dee,

termined by the size of the stove or furnace,

the nature of the fuel etc or rather by the volume per unit of time ofunburned products of combustion normally passing out through the pipe.

The highly heated air enters theflue or the fire box and readily reactsupon the products of combustion therein without materi- Fig. 2 showsmetal tubes 21 and 23 eX- tending along the inner andouter surfaces ofthe pipe section 20 respectively. One or more openings 25 in the wall ofthe outer tube 23 admit air to the outer chamber 24;; one or moreopenings 26 in the wall of the pipe section 20 admit the partly heatedair to the inner chamber 22 and perforations 27 in the wall of the innertube 21 distribute the air into the interior of section 20. The totaldistance which the air has to travel is thus nearly equal to thecircumference of the pipe section 20. If the pipe section 20 has adiameter of 6 inches, the air is brought into contact with a heatedstrip approximately 18 inches long.

While I have found thatthe embodiments disclosed give completesatisfaction in practially thereof may be carried out in various otherwcys. V

entiallydisposed air chamber may be'varied The length of the circumfertosuit particular requirements. For instance in place of a single annularair cham-' her a plurality of such chambers may be provided, suitablyinter-connected by com- 'municating passages so that the total length ofthe heated surface with which the air is brought into contact iscorrespondingly increased. 7 i Y By making'the air chamber spiral inform, the length thereof may be increased to any desired extent.

For these reasons the term circumferen tial is intended to include allair chambers prescribing for the air to be heated, a course which has 'acircumferential component,

In practice the relation between'the, nipple of a stove and the openingconnecting the pipe to the chimney'is'oftensuch that a pipe section ofthe ordinary length isnot available for attachment to the nipple. Sincethe length of pipe sectionembodymg my invention may be reduced to aminimum, it is of substantially universal application.

While my invention has been illustrated and described in connection witha stove, it

is obviously applicable to all combustion chambers which are connectedby a smoke V pipe with a flue or chimney.

In the claims the term short is intended to have reference to a lengthequal to the widthof the air chamber and small end portions justsufficient to make connection to 'ture.

2. As an article of manufacture, a pipe section adapted to form a partof a duct for leading away the products ofcombustion from a combustionchamber, and means extending 'circumferentially along the outer surfaceof'the pipe section and defining therewith a narrow air chamber, meansextending circumferentially along the inner surface of the pipe sectionand defining therewith an air chamber narrow lengthwise" c 6 of thepipe, the outer chamber having an air inlet and the inner chambercommunicating at one end with the outer chamber and at' the otherendwith the interiorof the pipe.

3. As an article of manufacture, a pipe section adapted to form a partof a duct for leading away the products of combustion from a combustionchamber, means extend ing circumferentially along the outer sur-v faceof' the pipe section and defining there'- with a relatively narrow airchamber, means extending circum'ferentially along the inner surface ofthe pipe section and defining.

therewith a second relatively narrow air chamber, the outer wall of theouter cha n her having an opening to admit air thereto,

the wall of the pipe section being perforated a at a point substantiallydiametrically oppo-f site said first opening to admit air into thesecond air chamber and a plurality of spaced openings remote from thesecond opening for admitting air from the second air chamber into theinterior of thepipe" section.

4. As an article of manufacture, a short pipe section adapted to form apart of a duct for leading away the products of coinbustion from acombustion chamber,and a narrow tubular element extendingcircumferentially along the'inner surface of the pipe section anddefining therewith an-air chamber, the walls of said air chamber beingperforated at points remote from each other for admitting air to thechamber and for connecting the chamber with the interior of the pipesection, respectively.

In testimony whereof, I afiix my signa :VJOHNBUDD SMITH.

